Example for geolocation: To centre the map on www.openstreetmap.org on your estimated location (supplied by your browser) click the arrow icon (3)

Geolocation – in relation to geo applications (e.g. a simple web map) – usually means the action that by some measurements or data (IP address, Wireless LAN access points, mobile phone cell ids, or even satellite-based positioning systems like GPS) an object's location (often: the user) is estimated and used.

Relation to OpenStreetMap

OSM itself does not offer a IP or Wireless LAN geolocation service itself or collect data for it. But of course you could use external geolocation providers and, for example, show this location on an OSM-based map.